Golf club head

ABSTRACT

A golf club head includes a face portion, a plurality of score lines formed in the face portion and extending in a toe-heel direction, a plurality of convex portions formed in the face portion at intervals in the toe-heel direction, extending in the toe-heel direction, and arranged as a plurality of arrays between the score lines adjacent to each other in a vertical direction of the face portion, and a plurality of concave portions formed in the face portion and extending in a direction, which intersects with the toe-heel direction, while passing between the convex portions adjacent to each other in the toe-heel direction.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to and the benefit of Japanese Patent Application No. 2018-119204 filed on Jun. 22, 2018, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a golf club head.

Description of the Related Art

There have been proposed golf club heads each of which includes a face portion in which grooves, concave portions, and convex portions thinner than score lines are formed (for example, US-2018-0036606, US-2017-0100792, Japanese Patent Laid-Open No. 2016-007537, Japanese Patent Nos. 6257635 and 6183191, Japanese Patent Laid-Open No. 2015-186513, and Japanese Patent No. 6065376). These grooves and the like are effective for increasing the spin amount on a struck ball or preventing a decrease in spin amount in, for example, rainy weather.

However, conventional golf club heads have room for improvement in terms of the drainage performance of the face portion and the spin amount on a struck ball.

SUMMARY OF THE INVENTION

It is an object of the present invention to improve the drainage performance of the face portion and the spin amount on a struck ball.

According to an aspect of the present invention, there is provided a golf club head that includes a face portion, comprising: a plurality of score lines formed in the face portion and extending in a toe-heel direction; a plurality of convex portions formed in the face portion at intervals in the toe-heel direction, extending in the toe-heel direction, and arranged as a plurality of arrays between the score lines adjacent to each other in a vertical direction of the face portion; and a plurality of concave portions formed in the face portion and extending in a direction, which intersects with the toe-heel direction, while passing between the convex portions adjacent to each other in the toe-heel direction.

Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an external view and a partial enlarged view of a golf club head according to an embodiment of the present invention;

FIG. 2 is a partial sectional perspective view of the golf club head shown in FIG. 1;

FIGS. 3A and 3B are sectional views of the golf club head shown in FIG. 1;

FIG. 4 is a view showing another formation example of convex portions and concave portions; and

FIGS. 5A to 5C are views showing an example of a manufacturing method.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1 shows an external view and a partial enlarged view of a golf club head A according to an embodiment of the present invention. FIG. 1 illustrates an example in which the present invention is applied to an iron type golf club head. The present invention is suitable for an iron type golf club head and, more particularly, for middle iron, short iron, and wedge type golf club heads. More specifically, the present invention is suitable for manufacturing a golf club head with a loft angle of 30° (inclusive) to 70° (inclusive) and a head weight of 240 g (inclusive) to 320 g (inclusive). However, the present invention is also applicable to wood type and utility (hybrid) type golf club heads.

The golf club head A includes a face portion 1 and a hosel portion 5. The face portion 1 forms a striking surface for striking a golf ball. A shaft (not shown) is attached to the hosel portion 5. In FIG. 1, an arrow d2 indicates a toe-heel direction, and reference symbols T and H indicate the toe side and the heel side, respectively. An arrow d1 indicates a vertical direction (top-sole direction) perpendicular to the toe-heel direction and along the face portion 1. Reference symbols U and L indicate the upper side and the lower side, respectively, upon grounding the sole portion of the head A.

A plurality of score lines 2, a plurality of convex portions 3, and a plurality of concave portions 4 are formed in the face portion 1. The concave portion 4 is a groove with a dimension different from that of the score line 2. In this embodiment, the concave portion 4 is a groove thinner than the score line 2.

The score lines 2, the convex portions 3, and the concave portions 4 will be described with reference to FIGS. 1 to 3B. FIG. 2 is a partial sectional perspective view of the golf club head A, and illustrates a part of the face portion 1 taken by cutting along the d1 direction and the d2 direction. FIG. 3A is a sectional view of the golf club head A taken along a line I-I in FIG. 1, and FIG. 3B is a sectional view of the golf club head A taken along a line II-II in FIG. 3A.

The respective score lines 2 are linear grooves extending in the d2 direction. The plurality of score lines 2 are aligned parallel to each other in the d1 direction. Although the score lines 2 are aligned at equal intervals (equal pitches) in this embodiment, they may be aligned at different intervals. In this embodiment, each score line 2 has the same cross-sectional shape throughout its entire longitudinal portion except for its two ends (toe- and heel-side ends). Also, the score lines 2 have the same cross-sectional shape.

Each score line 2 includes a pair of side walls (side portions) 21 and a bottom wall (bottom portion) 22, and has a trapezoidal cross-sectional shape bilaterally symmetric about a center line in the d1 direction. Note that the cross-sectional shape of the score line 2 is not limited to a trapezoidal shape, and may be other shapes such as a V shape. Rounded portions are formed on edges 23 of each score line 2. The radius of the rounded portion is, for example, 0.05 mm (inclusive) to 0.3 mm (inclusive). The face portion 1 includes a reference plane FS. The reference plane FS is a flat plane and includes portions adjacent to the edges 23 of the score lines 2. In other word, a virtual plane including the planes adjacent to the edges 23 is the reference plane FS.

A depth Ds of the score line 2 (the distance between the bottom wall 22 and the reference plane FS) is preferably 0.3 mm or more. When the golf club head A is intended for athletics, the depth Ds is set to 0.5 mm or less to comply with a relevant rule. A width Ws (the width defined by the 30-degree measurement rule) of the score line 2 is preferably 0.6 mm or more. When the golf club head A is intended for athletics, the width Ws is set to 0.9 mm or less to comply with a relevant rule.

The respective convex portions 3 are protrusions protruding from the reference plane FS and extending in the d2 direction. At the time of striking a golf ball, its surface is readily caught between the convex portions 3 so that the spin amount can be increased. In this embodiment, the respective convex portions 3 extend parallel to the score lines 2. However, the respective convex portions 3 may extend obliquely with respect to the score lines 2. In this embodiment, when viewing in the d2 direction, the plurality of convex portions 3 are formed at intervals IT. When viewing in the d1 direction, a plurality of arrays of convex portions 3 (five arrays of convex portions 3 in this example) are formed between two score lines 2 adjacent to each other in the d1 direction. The height (a protruding amount from the reference plane FS) of the convex portion 3 is, for example, 10 μm to 25 μm. The width (the width in the d1 direction on the reference plane FS) of the convex portion 3 is, for example, 100 μm to 600 μm. The cross-sectional shape of the convex portion 3 in the d1 direction in this embodiment is a chevron shape. However, the cross-sectional shape of the convex portion 3 may be a rectangle or a circular arced shape.

The concave portion 4 is a groove recessed from the reference plane FS and extends in a direction intersecting with the d2 direction. Since the concave portions 4 are formed, it becomes possible to drain water (such as rainwater) on the face portion 1 into the concave portions 4 so that the drainage performance of the face portion 1 can be improved. In this embodiment, the concave portion 4 extends linearly. Although the concave portion 4 extends in a direction perpendicular to the d2 direction, that is, in the d1 direction in this embodiment, the extending direction of the concave portion 4 may be oblique with respect to the d1 direction. In this embodiment, the concave portions 4 are aligned at equal intervals in the d2 direction, and the interval is, for example, 3 mm to 8 mm.

The concave portion 4 extends while passing between the convex portions 3 adjacent to each other in the d2 direction (a portion corresponding to the interval IT). Although water is readily trapped between the convex portions 3 adjacent to each other in the d1 direction, since the concave portion 4 is formed to traverse these convex portions 3, trapped water can be effectively drained into the concave portions 4.

In this embodiment, the concave portion 4 communicates with two score lines 2 adjacent to each other in the d1 direction. It is also possible to adopt an arrangement in which the concave portion 4 does not communicate with the score lines 2. However, when the concave portion 4 communicates with the score lines 2, water on the face portion 1 readily flows from the concave portion 4 to the score line 2 so that the drainage performance of the face portion 1 can be further improved.

In addition, since the concave portions 4 are aligned at equal pitches in the d2 direction in this embodiment, the drainage performance of the face portion 1 can be evenly improved.

The improvement in the drainage performance of the face portion 1 enhances the effect of suppressing a decrease in back spin amount in, for example, rainy weather. Note that although one concave portion 4 passes between the convex portions 3 adjacent to each other in the d2 direction (the portion corresponding to the interval IT) in this embodiment, the plurality of concave portions 4 may be arranged to pass there. In this case, the drainage performance can be further improved.

The depth of the concave portion 4 (the distance from the reference plane FS to the deepest part of the concave portion 4) is, for example, 5 μm to 25 μm. The width (the width on the reference plane FS in the d2 direction) of the concave portion 4 is, for example, 30 μm to 200 μm. In this embodiment, the cross-sectional shape of the concave portion 4 along the d2 direction is a triangular shape, and particularly an isosceles triangular shape (V shape). The isosceles triangular cross-sectional shape of the concave portion 4 makes it possible to form a narrower water channel. In addition to facilitate a capillary phenomenon, this can prevent dust such as grass from clogging in the concave portion 4. However, the cross-sectional shape of the concave portion 4 may be a rectangle or a circular arced shape.

As described above, in this embodiment, formation of the convex portions 3 and the concave portions 4 makes it possible to achieve both of an increase in back spin amount and the effect of suppressing a decrease in back spin amount in, for example, rainy weather owing to improvement in the drainage performance. That is, improvement in the drainage performance of the face portion 1 and that in the spin amount on a struck ball can be achieved.

Next, another formation example of the convex portions 3 and the concave portions 4 will be described with reference to FIG. 4. Although the concave portions 4 extend linearly in the example shown in FIGS. 1 to 3B, they may extend arcuately. FIG. 4 shows its example.

In the example shown in FIG. 4, the plurality of concave portions 4 extend arcuately and, more specifically, extend concentrically centering on a center 10. The concave portions 4 adjacent to each other are aligned at equal intervals when viewing from the center 10 in a radial direction. This interval is, for example, 3 mm to 8 mm. The concave portions 4 adjacent to each other may be aligned at different pitches, or may not be aligned concentrically. The concave portions 4 shown in FIG. 4 also communicate with the score lines 2, but it is possible to adopt an arrangement in which the concave portions 4 do not communicate with the score lines 2.

The center 10 is located on the toe side in the d2 direction and on the upper side in the d1 direction when using the center portion of the face portion 1 as a reference. Therefore, each concave portion 4 has a circular arc shape that bulges toward the heel side in the d2 direction and toward the lower side in the d1 direction. When striking a golf ball while opening the face portion 1, the surface of the golf ball may be caught on the edge of the concave portion 4, resulting in an increase in spin amount. That is, the example of the concave portions 4 shown in FIG. 4 can contribute to an increase in spin amount in addition to improvement in the drainage performance.

Also in the example shown in FIG. 4, the plurality of convex portions 3 are formed at intervals in the d2 direction, and the concave portion 4 passes the portion corresponding to the interval. Different from the example shown in FIGS. 1 to 3B, the position of the interval in the d2 direction is different for each array of convex portions 3 in the example shown in FIG. 4. In the example shown in FIG. 4, one concave portion 4 passes the portion corresponding to the interval between the convex portions, but the plurality of concave portions 4 may pass there.

A formation method of the convex portions 3 and the concave portions 4 will be described next. As the golf club head A, for example, a primary molded product without the convex portions 3 and the concave portions 4 is manufactured by forging or casting. Then, the convex portions 3 and the concave portions 4 are formed in the primary molded product. After that, coating and a surface treatment are performed to complete the golf club head A. The primary molded product may be formed with or without the score lines 2. When the primary molded product includes no score line 2, it is possible to form the score lines 2 upon forming the convex portions 3 and the concave portions 4. The primary molded product may be formed from a single member or multiple members. When the primary molded product is formed from multiple members, it may be formed from, for example, a face forming member which forms the face portion 1 and a head body which forms the part other than the face portion 1. In this case, the face forming member and the head body may be combined after the convex portions 3 and the concave portions 4 are formed in the face forming member.

The convex portions 3 and the concave portions 4 can be formed by laser processing or cutting. FIGS. 5A and 5B exemplify a case in which the convex portions 3 and the concave portions 4 are formed by laser processing. A primary molded product A′ in which the convex portions 3 and the concave portions 4 are to be formed is fixed to a laser irradiation device (not shown) via a jig 100. The laser irradiation device includes an irradiation unit 101 which emits laser light. In the example shown in FIGS. 1 to 3B, the convex portions 3 are formed while irradiating the face portion 1 with laser light emitted by the irradiation unit 101, and relatively moving the face portion 1 (primary molded product A′) or irradiation unit 101 in the d2 direction. In addition, the concave portions 4 are formed while irradiating the face portion 1 with laser light emitted by the irradiation unit 101, and relatively moving the face portion 1 (primary molded product A′) or irradiation unit 101 in the d1 direction. In the example shown in FIG. 4, the concave portions 4 are formed while relatively moving the face portion 1 (primary molded product A′) or irradiation unit 101 on circular arc tracks.

FIG. 5C exemplifies a case in which the convex portions 3 and the concave portions 4 are formed by cutting. The primary molded product A′ is fixed to an NC milling machine via the jig 100. The NC milling machine includes a spindle 102 that is rotatably driven about the Z-axis, and a cutting tool (end mill) 103 is attached to the lower end of the spindle 102. As in the case of laser processing, in the example shown in FIGS. 1 to 3B, the convex portions 3 are formed while relatively moving the face portion 1 (primary molded product A′) or cutting tool 103 in the d2 direction. In addition, the concave portions 4 are formed while relatively moving the face portion 1 (primary molded product A′) or cutting tool 103 in the d1 direction. In the example shown in FIG. 4, the concave portions 4 are formed while relatively moving the face portion 1 (primary molded product A′) or cutting tool 103 on circular arc tracks.

Note that the formation method may be different between the convex portions 3 and the concave portions 4. For example, the convex portions 3 may be formed by cutting, and the concave portions 4 may be formed by laser processing. The concave portions 4 are preferably formed by laser processing using laser with a short pulse width. This can suppress the thermal effect due to laser irradiation, thereby facilitating formation of thinner grooves.

Note that after the formation of the convex portions 3 and the concave portions 4, a surface treatment for increasing the hardness of the face portion 1 is preferably performed. Examples of such a surface treatment are a carburizing treatment, nitriding treatment, soft nitriding treatment, PVD (Physical Vapor Deposition) treatment, ion plating, DLC (Diamond-Like Carbon) treatment, and plating treatment. Especially surface treatments such as a carburizing treatment and nitriding treatment, which modify the surface without forming another metal layer on the surface, are preferable. The surface of the face portion 1 may be covered with a plating layer.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 

What is claimed is:
 1. A golf club head that includes a face portion, comprising: a plurality of score lines formed in the face portion and extending in a toe-heel direction; a plurality of convex portions formed in the face portion at intervals in the toe-heel direction, extending in the toe-heel direction, and arranged as a plurality of arrays between the score lines adjacent to each other in a vertical direction of the face portion; and a plurality of concave portions formed in the face portion and extending in a direction, which intersects with the toe-heel direction, while passing between the convex portions adjacent to each other in the toe-heel direction.
 2. The golf club head according to claim 1, wherein the plurality of concave portions extend linearly.
 3. The golf club head according to claim 2, wherein the plurality of concave portions are formed at equal pitches in the toe-heel direction.
 4. The golf club head according to claim 1, wherein the plurality of concave portions extend arcuately.
 5. The golf club head according to claim 1, wherein each of the plurality of concave portions has a circular arc shape that bulges toward a heel side in the toe-heel direction and toward a lower side in the vertical direction.
 6. The golf club head according to claim 1, wherein the plurality of concave portions communicate with the score lines. 